The carbamate herbicides CIPC and IPC cause microtubule disassembly and growth inhibition in mammalian cells. Their withdrawal enables growth to resume but with severely perturbed mitosis, including development of multipolar spindles and production of multinucleated and micronucleated cells. We intend to measure the effects of CIPC treatment and withdrawal on the duration of mitosis and its component phases. Immunofluorescence techniques based on antitubulin, anticentriole and anti MAP antibodies will be applied to study the replication and migration at early prophase of centrioles in CIPC-treated cells; and to study the interaction of microtubule-associated proteins with microtubules after herbicide treatment.